/*
 * Copyright 2014 TeamWin
 * This file is part of TWRP/TeamWin Recovery Project.
 *
 * TWRP is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * TWRP is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with TWRP.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <algorithm>

#include <string>
#include <vector>
#include <dirent.h>
#include <stdlib.h>

#include "mblog/logging.h"

#include "find_file.hpp"
#include "twrp-functions.hpp"

#define LOG_TAG "mbbootui/find_file"

std::string Find_File::Find(const std::string& file_name, const std::string& start_path)
{
    return Find_File().Find_Internal(file_name, start_path);
}

Find_File::Find_File()
{
}

std::string Find_File::Find_Internal(const std::string& filename, const std::string& starting_path)
{
    DIR *d;
    std::string new_path, return_path;
    std::vector<std::string> dirs;
    std::vector<std::string> symlinks;
    unsigned index;

    // Check to see if we have already searched this directory to prevent infinite loops
    if (std::find(searched_dirs.begin(), searched_dirs.end(), starting_path) != searched_dirs.end()) {
        return "";
    }
    searched_dirs.push_back(starting_path);

    d = opendir(starting_path.c_str());
    if (d == nullptr) {
        LOGI("Find_File: Error opening '%s'", starting_path.c_str());
        return "";
    }

    struct dirent *p;
    while ((p = readdir(d))) {
        if (!strcmp(p->d_name, ".") || !strcmp(p->d_name, "..")) {
            continue;
        }
        new_path = starting_path + "/";
        new_path.append(p->d_name);
        if (p->d_type == DT_DIR) {
            // Add dir to search list for later
            dirs.push_back(new_path);
        } else if (p->d_type == DT_LNK) {
            // Add symlink to search list for later
            symlinks.push_back(new_path);
        } else if (p->d_type == DT_REG && filename == p->d_name) {
            // We found a match!
            closedir(d);
            return new_path;
        }
    }
    closedir(d);

    // Scan real directories first if no match found in this path
    for (index = 0; index < dirs.size(); index++) {
        return_path = Find_Internal(filename, dirs.at(index));
        if (!return_path.empty()) {
            return return_path;
        }
    }
    // Scan symlinks after scanning real directories
    for (index = 0; index < symlinks.size(); index++) {
        char buf[PATH_MAX];
        // Resolve symlink to a real path
        char* ret = realpath(symlinks.at(index).c_str(), buf);
        if (ret) {
            return_path = Find_Internal(filename, buf);
            if (!return_path.empty()) {
                return return_path;
            }
        }
    }
    return "";
}
